Glasswool

Glasswool: the high performing insulation

ISOVER glasswool products offer state-of-the-art insulation, constantly improved and developed by Saint-Gobain ISOVER over more than 70 years to ensure that they provide the very highest levels of consistent quality and performance, with dozens of new patents filed every year.

Manufactured from locally-sourced natural raw materials like sand, ISOVER glasswool products today include up to 80% recycled glass, making them the perfect choice to meet environmental concerns.

Glasswool production

Glasswool is made from natural sand to which recycled glass (cullet) and fluxing agents are added. The material is melted to 1100°C in an electric furnace, and then forced through precision drilled holes in high speed spinning disks, to form fibres. Binding products and other additives required to give specific characteristics to different products are then added as fibres fall onto moving collection belts. The glasswool mat is then polymerised, heated and passed through compression rollers where it is cured to provide a product of the required thickness and density. The finished products are then packaged under high compression to reduce the volume and cost of storage and transportation.

Manufacturing process

1. Composition

Glasswool is made mainly of sand, soda-ash, limestone and recycled glasses. The raw materials are stored in silos, automatically weighed, mixed and poured into the furnace by an automatic batch feeder.

2. Glasswool melting

The melting of the mix is obtained at a temperature exceeding 1400°C in an electrical furnace.

3. TEL fiberizing, binder

Through a feeder, the glass flows to the fiberizing machine. When flowing so, the glass reaches the required temperature to be converted into fibres. The main part of the TEL fiberizing machine is the centrifugal spinner rotating around a vertical axis. The band of this spinner in refractory steel is drilled with a multiplicity of holes of about 1 mm diameter each.
Glass is centrifugally pushed through these holes and divided into a multiplicity of primary streams. A strong jet of hot gases realise then the final "etirage" of the fibres. A binder is sprayed automatically on the fibres by spray nozzles.

4. Forming, curing

The products impregnated with resins are then taken to a curing oven heated at 250°C. The hot air flows through the glasswool blanket and, while curing the fibres, gives a correct rigidity. The binder becomes yellow.

5. Cutting

At the exit of the curing oven, circular saws or high pressure water jets split the blanket according to its trade width. the final presentation varies from rools to slabs, according to the end-use application. Off-cuts are also recycled into the production process. The belt then transports the blanket to a gluing station where it can receive either a vapour barrier facing paper or aluminium, or a bonded mat or PVC coating.

6. Packaging, palletisation

The end of the line is generally equipped with a rooling machine for mats and a stacking machine for boards.
The glasswool can be compressed to up to a tenth of its volume reducing considerably transport and storage expenses as well as wastes on sites. Units are then gathered on pallets improving efficiency of logistics operations.
On a pallet, 36 rolls of glass can be packed up.